Summary:
The ketogenic diet, which is low in carbohydrates, high in fat, and moderate in protein, promotes ketone production and improves insulin sensitivity. Given that insulin resistance is a key feature of both type 2 diabetes and polycystic ovary syndrome (PCOS), ketogenic diets may offer therapeutic benefits for women with these conditions. This study is a systematic review and meta-analysis examining the effects of a ketogenic diet in women with PCOS. PCOS is a common endocrine disorder in reproductive-aged women, characterized by irregular ovulation, polycystic ovaries, and high androgen levels. It is often accompanied by obesity, insulin resistance, and an increased risk of type 2 diabetes and cardiovascular disease. Treatment typically depends on symptoms and reproductive goals, including hormonal contraceptives, metformin, and lifestyle interventions such as diet and weight loss. The review included 15 studies, with 10 suitable for meta-analysis. Most participants were classified as overweight (a BMI greater than 25). In women following a ketogenic diet, significant improvements were observed in BMI, body weight, waist circumference, luteinizing hormone (LH) levels, menstrual cycle regularity, and insulin resistance. When compared to other diets, ketogenic interventions showed greater reductions in weight, BMI, LH levels, and insulin resistance, although effects on androgen levels and lipid profiles were inconsistent. Overall, this study suggests that the ketogenic diet may be an effective strategy to improve metabolic and reproductive outcomes in women with PCOS who are overweight.
Abstract:
Background and Aim: Polycystic ovary syndrome (PCOS) is a common endocrine disorder linked to obesity, insulin resistance, and reproductive dysfunction. While dietary modification is central to management, the optimal approach remains unclear. This systematic review and meta-analysis evaluated the effects of the ketogenic diet on anthropometric, metabolic, and endocrinological outcomes in women with PCOS. Methods: A systematic search of five databases (inception–February 2025) identified studies reporting outcomes in women with PCOS following a ketogenic diet. Meta-analyses compared pre- and post-ketogenic diet outcomes (primary analysis) and ketogenic diet versus other diets (secondary analysis). Summary mean differences (MDs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Risk of bias and evidence quality were assessed using validated tools and the GRADE approach. Results: Fifteen studies were included in the review, of which ten met the criteria for inclusion in the meta-analysis. Most participants in the included studies had a BMI exceeding 25 kg/m2. In the primary analysis, ketogenic diet led to significant reductions in BMI (MD: -3.38 kg/m2, 95% CI: 2.53 to 4.23, I2=0%), weight (MD: -10.77 kg, 95% CI: 8.73 to 12.81, I2=0%), and waist circumference (MD: -8.93 cm, 95% CI: 5.66 to 12.19; I2=44%). Reductions were also observed in luteinizing hormone (LH) levels (MD: 4.07, 95% CI: 3.36 to 4.79, I2 = 0%), menstrual cycle duration (MD: 26.06, 95% CI: 2.28 to 49.85, I2=68%), and insulin resistance (MD: 2.43; 95% CI: 1.16 to 3.69, I2=95%). In the secondary analysis, ketogenic diet showed superior effects on BMI (MD: -1.65, 95% CI: -2.76 to -0.55, I2 = 0%) and weight loss (MD: -4.98, 95% CI: -9.05 to -0.91, I2=7%) as well as LH levels (MD 1.68, 95% CI: -3.18 to -0.19, I2=30%) and insulin resistance (MD: -1.71, 95% CI: -2.98 to -0.43, I2=90%) compared to other diets, though results for androgen and lipid parameters were inconsistent. Heterogeneity was high for most of the studied outcomes. Conclusion: The ketogenic diet appears to be a promising dietary intervention for improving weight, insulin sensitivity, and reproductive hormone profiles in women with PCOS and a BMI exceeding 25 kg/m2. Nonetheless, the considerable heterogeneity among included studies and variations in study quality warrant cautious interpretation of these findings. Further high-quality, long-term randomized controlled trials are needed to more definitively establish the efficacy and safety of the ketogenic diet in women with PCOS.
Article Publication Date: 3/12/2025
DOI: 10.1016/j.clnu.2025.11.019
